Steam ironing device

ABSTRACT

A steam ironing device ( 10 ) provides an ionized steam output using an ionizing arrangement ( 30 ). The ionization process, in particular the high energy electric discharge used for ionization, breaks down steam particles into finer particles. As a result, a greater proportion of the steam particles generated can penetrate into the fabric of the garment being ironed, to improve fabric treatment and fabric moistening.

This invention relates to a steam ironing device, such as a steam iron with integrated water reservoir, a steam ironing system with separate steam boiler or integrated steam ironing system in which a boiler or steam generator is integrated with an ironing board.

Steam irons are a well-known domestic appliance.

A conventional steam iron comprises a soleplate heated by an electric heating element. The temperature of the soleplate is kept at a desired temperature by means of a thermostat and a temperature dial. Steam is generated by a steam generator, which comprises a water tank, a water-dosing pump, and a steam chamber. The water pump pumps water from the water tank to the steam chamber (as drips rather than a large flow of water) via a hose under command of a pump signal from an electric control device. The rate at which water is supplied dictates the amount of steam being produced, and the amount of steam is sufficiently low that the temperature of the sole plate is not significantly affected.

Instead of a pumped system, water can be dosed to the steam chamber under gravity.

The steam chamber is typically heated by the soleplate, but an auxiliary heating element may instead be provided.

The steam from the steam chamber reaches steam vents provided in the base of the sole plate.

The steam produced by steam irons serves to dampen the fabric to be ironed. The application of moisture to a garment during ironing makes the ironing process easier, and reduces the time taken. In particular, the weakness of some fibres increases with the water content, especially cotton, linen, viscose and wool. The application of moisture thus conditions the fabric for subsequent ironing. This ironing process is essentially a relaxation process by which the fibres recover from the plastic deformation caused by wearing of the clothing. An alternative to the application of steam is the use of a cold-water spray or pre-dampening of a garment before ironing.

In the usual steam ironing device the moisturizing of the garment is not optimal under all conditions. The objective of the invention is to improve the ease and/or the performance of steam ironing.

According to a first aspect of the invention, there is provided a steam ironing device comprising an iron with a sole plate for pressing against an article to be ironed, a water reservoir and steam generating means, wherein the ironing device further comprises means for providing an electrically charged steam output to the article being ironed. By this measure the objective of the invention is achieved, particularly, the penetration of droplets into the fabric to be ironed is improved, moreover the condensation rate is increased.

Preferably, the electric charging is achieved using an ionization arrangement. It has been found that the ionization process, in particular the high energy electric discharge used for ionization, can break down steam droplets into finer droplets. As a result, a greater proportion, than in a usual steam iron, of the steam droplets generated can penetrate into the fabric of the garment being ironed.

The ionization also charges the water molecules either positively or negatively, depending on the type of ionizer used.

The finer steam also presents an increased steam droplet surface area, enabling a more rapid dissipation of heat. This allows an increased level of condensation for conditioning the fabric.

The effectiveness of the steam application is therefore significantly improved.

The steam output also has increased visibility compared to superheated dry steam, and this assists the operator of the iron.

The sole plate is preferably heated.

The iron preferably comprises a steam chamber having steam outlet nozzles, and an electrode arrangement is provided within the steam chamber.

For example, the electrode arrangement may comprise at least two electrodes to which different voltages are applied. These then provide a field which induces ionization. The electrode arrangement may instead comprise at least two electrodes to which a first voltage is applied, and the steam chamber can defines a further ground electrode. The water molecules in the vicinity of the electrodes are then charged to the same polarity.

For example, substantially only negative negatively charged water droplets may be provided in the stream output. It has been found that fabric tends to be positively charged, and the generation of negatively charged steam droplets takes advantage of this by allowing electrostatic attraction of the steam droplets to the fabric. This makes the use of the generated steam more efficient.

The at least two electrodes can extend into the nozzles, thereby providing ionization/charging at the steam nozzle outlets.

An electrode arrangement may instead be provided at the nozzles, and external of the steam chamber.

The same heater arrangement may be used for generating the steam as for the sole plate, or else different hearing arrangements may be used.

In another arrangement, an ionized air flow is provided and is mixed with steam.

A venturi mixing device may be used. The steam may again be provided by a steam chamber, heated by the sole plate heater.

In addition to an iron with all of the components integrated into the iron casing, the invention can be applied to a steam ironing system with separate steam boiler, or to an integrated steam ironing system in which a boiler or steam generator is integrated with an ironing board.

The invention also provides an ironing method comprising applying electrically charged steam to a garment during ironing.

The invention also provides a steam ironing system comprising: an iron with a sole plate for pressing against an article to be ironed; an ironing board; a water reservoir and steam generating means; and means for providing an electrically charged steam output to the article being ironed.

According to a second aspect of the invention, there is provided a steam ironing system comprising an iron with a sole plate for pressing against an article to be ironed and steam generating means for providing a steam output comprising steam droplets, for application the article being ironed, wherein at least 40% of the steam droplets in the steam output have a droplet size of less than 10 microns.

Examples of the invention will now be described in detail with reference to the accompanying drawings, in which:

FIG. 1 shows a first example of steam iron in accordance with the invention;

FIG. 2 shows in more detail part of the iron with the steam chamber of the iron of FIG. 1;

FIG. 3 shows a second example in more detail of part of the iron with the steam chamber of the iron in accordance with the invention;

FIG. 4 shows a third example in more detail of part of the iron with the steam chamber of the iron in accordance with the invention; and

FIG. 5 shows an ironing system of the invention, in which the steam generation is integrated into an ironing board.

FIG. 1 shows a first example of iron in accordance with the invention.

The iron comprises a metal soleplate 12 heated by an electric heating element 14. The temperature of the soleplate is kept at a desired temperature by means of a thermostat and a temperature dial 16. Steam is generated by a steam generator, which comprises a water tank 18, a water-dosing pump 20, and a steam chamber 22. The water pump 20 pumps water from the water tank 18 to the steam chamber 22 via a hose under command of a pump signal from a control processor 24.

In the example shown, the steam chamber 22 is heated by the soleplate 12, but an auxiliary heating element may instead be provided so that the water chamber 18 can be implemented as a separate boiler.

The steam from the steam chamber is routed to steam vents 26 in the base of the sole plate.

The iron of the invention is conventional to the extent described above.

In accordance with the invention, the steam iron is provided with means for charging the steam output. In FIG. 1, this charging means comprises ionization electrodes 30 powered by an appropriate power source 32, and provided within the steam chamber 22. These electrodes induce high energy electric discharge within the steam formed in the steam chamber.

The ionization process breaks down the steam into finer droplets. As a result, a greater proportion of the steam droplets generated can penetrate into the fabric of the garment being ironed. This provides improved penetration of the droplets into the fabric and also gives an increase in condensation rate.

The ionization process charges the water molecules, and it may also ionize the surrounding air. The resulting charged steam resists formation of large droplets as a result of electric repulsion, both in transit and during deposition, and the droplet size is also more uniform.

The use of ionization has been proposed in various domestic appliance applications, for different reasons, and the use of ionization within a steam iron also provides corresponding subsidiary benefits.

For example, the use of air ionization systems have been proposed in order to provide anti-bacterial and deodorizing properties. Negative ions in particular have been found to posses these properties.

For a steam iron, the use of ionization can therefore also provide deodorizing benefits both for the garment being ironed and for the surrounding air, which is of course in the vicinity of the user of the iron.

The charged steam flow also serves to reduce fabric static electricity.

A further benefit is that ions resulting from the ionization process can be electrostatically attracted to the garment. It has been found that fabric tends to be positively charged (by a process of giving up surface electrons). This tendency to give up surface electrons is dependent on the dampness of the fabric, but in all cases, the generation of negative ions takes advantage of this by allowing electrostatic attraction of the ionized steam to the fabric.

The ionization can be achieved in conventional manner. Essentially, a pair of electrodes disposed closely adjacent between a high frequency alternating field is applied will produce high corona discharge energy. The energy of a high energy corona discharge can reduce droplet size, and the emitters in an ac system will emit positive and negative ions alternately. Alternatively, a dc ionizer may be used and can emit one ion charge only.

FIGS. 2 to 4 show in more detail possible implementations of the invention. In each case, the sole plate 12 is shown, and the steam chamber 22 is integral with the sole plate and heated by the sole plate heater 14. The water supply to the steam chamber is shown schematically as 38.

In FIG. 2, the electrodes 30 of the ionizer 40 extend through the steam chamber, with insulating inserts 42 isolating the electrodes 30 from the sole plate metal. Each electrode 30 extends into the nozzle opening 26, and thereby provides charging of the steam exiting the nozzle.

In FIG. 3, the electrodes 30 are of the same polarity, and the other electrode is defined by the sole plate itself, which is at ground potential. Thus, one of the output terminals 44 of the ionizer 40 is ground.

In FIG. 4, instead of the ionizer electrodes being provided in the steam chamber, they are provided at the nozzle outputs 26.

In all examples above, the steam chamber content or output flows past the ionizer electrodes. Instead, the steam chamber output can be mixed with ionized air. The Venturi effect can be used to provide passive mixing of the steam with a source of ionized air.

In the examples above, the steam chamber is heated by the sole plate. It is equally possible for a separately powered steam generator to enable completely independent control of the sole plate heating function and the steam generation function.

As mentioned above, ionization can be induced by an alternating current field or a direct current field. A large negative voltage applied to the electrodes can provide the generation of negative ions, which are associated with the deodorizing properties and reduction in particulate impurities. The implementation of the ionizing function, in particular the required electrode designs and voltage drive schemes, will be routine to those skilled in the art.

There may be additional functions implemented by the processor 24, but these additional functions are not relevant to this invention, and for this reason, only an overview of the operation the steam iron has been given. The invention can be applied to all types of known steam irons, and accordingly many different variations will be apparent to those skilled in the art.

The detailed examples given all relate to a steam iron in which the water reservoir and steam generation is internal to the iron. There are other types of ironing device to which the invention can be applied, and which are intended to be within the scope of this application.

Steam ironing “systems” are known, in which a separate external steam boiler is provided. This boiler can be mounted on a stand, and steam is supplied from the boiler to the iron by a connecting steam hose. The steam hose can also provide the electric power lines to the iron. In this case, the ionization can be provided in the iron itself or in the external boiler. The boiler in the stand may have a separate water reservoir for feeding water to the boiler as needed. Instead of an external boiler, the steam generation may be in the iron, and only an external water reservoir is provided in the iron stand. In this case, a pump feeds the water from the water reservoir into the iron, and the water hose can again provide the electric power lines to the iron.

Ironing system are also known in which the external boiler or steam generator is integrated with an ironing board. The ironing board may be provided with additional functions, such as heating for the board and a fan.

FIG. 5 shows an ironing system comprising a board 50 which is provided with the ionized steam generation system 52 and an iron 54. The steam generation system can deliver steam to the iron for subsequent application to the article being ironed, or else the steam generation system 52 can apply the steam directly to the article being ironed.

The water supply to the steam chamber can be pumped or under gravity.

In the example above, the iron sole plate is heated. However, it is possible for the heating to be carried out separately (including heating by means of the applied steam), and the iron sole plate is then purely for pressing.

The examples above each use an ionization arrangement to charge the steam output and also to provide finer steam droplets.

A steam output with fine droplets can provide the advantages as outlined above without needing the droplets to be charged. The invention therefore also provides a steam ironing device in which at least 40% of the steam droplets in the steam output provided to the garment during ironing have a droplet size of less than 10 microns.

More preferably, at least 50% of the steam droplets have a diameter of less than 10 microns.

In further preferred examples, at least 40% of the steam droplets in the steam output provided to the garment during ironing have a droplet size of less than 7 microns, and more preferably, at least 50% of the steam droplets have a diameter of less than 7 microns.

In further preferred examples, at least 40% of the steam droplets in the steam output provided to the garment during ironing have a droplet size of less than 5 microns, and more preferably, at least 50% of the steam droplets have a diameter of less than 5 microns. For example 50%-75%, or 55%-65% of the steam droplets have a diameter of less than 5 microns.

By providing a more uniform and small size droplet spread, the ironing performance is improved.

These droplet sizes can be achieved using the ionization process, but other processes are possible, for example using a mechanical arrangement or an ultrasound arrangement. The steam nozzle designs and layout can also be optimised for a particular desired droplet size.

Various other modifications will be apparent to those skilled in the art. 

1. A steam ironing device comprising an iron with a sob plate, a water reservoir and steam generating means, wherein the ironing device further comprises means for providing an electrically charged steam output to the article being ironed.
 2. A device as claimed in claim 1, provided with heating means for heating the sole plate.
 3. A device as claimed in claim 1, comprising a steam chamber having steam outlet nozzles, and wherein the means for providing an electrically charged output comprises an electrode arrangement within the steam chamber.
 4. A device as claimed in claim 3, wherein the electrode arrangement comprises at least two electrodes to which different voltages are applied.
 5. A device as claimed in claim 3, wherein the electrode arrangement comprises at least two electrodes to which a first voltage is applied, and wherein the steam chamber defines a further ground electrode.
 6. A device as claimed in claim 4, wherein the at least two electrodes extend into the nozzles.
 7. A device as claimed in claim 1, comprising a steam chamber having steam outlet nozzles, and wherein the means for providing an electrically charged output comprises an electrode arrangement provided at the outlet of the nozzles.
 8. A device as claimed in claim 1, wherein the means for providing an ionized output provides negative ions.
 9. A device as claimed in claim 1, wherein die means for providing an electrically charged output comprises means for providing an ionized air flow and for mixing the ionized air flow with steam.
 10. A device as claimed in claim 9, comprising a steam chamber having outlet nozzles to provide the steam for mixing with the ionized air flow.
 11. A device as claimed in claim 1, wherein the water reservoir, the steam generating means and the means for providing an electrically charged steam output to the article being ironed are provided in the iron.
 12. A device as claimed in claim 10, wherein a heater arrangement is provided for heating the sole plate, and the steam chamber is heated by the same heater arrangement as the sole plate.
 13. A device as claimed in claim 1, wherein the water reservoir is external to the iron.
 14. A device as claimed in claim 13, wherein the steam generating means is external to the iron.
 15. A device as claimed in claim 1, wherein an electric pump is provided for controlling the flow of water from the water reservoir to the steam generating means.
 16. An ironing system comprising a device as claim 13, and an ironing board, wherein the water reservoir is housed by the ironing board.
 17. An ironing method comprising applying electrically charged steam to a garment during ironing, the ironing comprising applying pressure to the garment using an iron sole plate.
 18. A steam ironing system comprising: an iron with a sole plate; an ironing board; a water reservoir and steam generating means; and means for providing an electrically charged steam output to the article being ironed.
 19. A system as claimed in claim 18, wherein the means for providing an electrically charged steam output to the article being ironed forms part, of the board.
 20. A steam ironing system comprising an iron with a sole plate for pressing against an article to be ironed steam generating means for providing a steam output comprising steam droplets, for application to the article being ironed, and an ionisation arrangement for breaking down steam droplets whereby at least 40% of the steam droplets in the steam output have a droplet size of less than 10 microns.
 21. A steam ironing system as claimed in claim 20, wherein at least 50% of the steam droplets in the steam output have a droplet size of less than 10 microns.
 22. A steam ironing system as claimed in claim 20, wherein at least 40% of the steam droplets in the steam output have a droplet size of less than 7 microns.
 23. A steam ironing system as claimed in claim 20, wherein at least 50% of the steam droplets in the steam output have a droplet size of less than 7 microns.
 24. A steam ironing system as claimed in claim 20, wherein at least 40% of the steam droplets in the steam output have a droplet size of less than 5 microns.
 25. A steam ironing system as claimed in claim 20, wherein at least 50% of the steam droplets in the steam output have a droplet size of less than 5 microns.
 26. A steam ironing system as claimed in claim 20, wherein at least 55%-65% of the steam droplets in the steam output have a droplet size of less than 5 microns.
 27. A steam ironing system as claimed in claim 20, comprising a steam iron, and wherein the steam generating means forms part of the iron.
 28. A steam ironing system as claimed in claim 20, comprising an iron and an ironing board, and wherein the steam generating means forms part of the ironing board.
 29. An ironing method comprising applying steam to a garment during ironing, the steam comprising steam droplets, with at least 40% of the steam droplets in the steam output having a droplet size of less than 10 microns, the method making use of the steam iron system according to claim
 20. 